Heat exchanger



L. HEDBOM HEAT EXCHANGER April 1, 1958 2 Sheets-Sheet 1* Filed NOV. 10, 1954 A ril 1, 1958 L.,HEDBOM 2,828,947

' I HEAT EXCHANGER Filed Nov. 10, 1954v z Sheets-Sheet z t f tes Patent HEAT EXCHANGER Lars Hedbom, Jonkoping, Sweden, assignor to Aktiebolaget Svenska Flaktfahriken, Stockholm, Sweden Application November 10, 1954, Serial No. 468,085 Claims priority, application Sweden November 11, 1953 4 Claims. I (Cl. 257-245) nection of the heat exchanger to ducts or similar passages and consisting of two L-iron frames being fastened to the outer partition plates of the heat exchanger and mutually joined by means of two frames of U-irons and interspaced crosswise extending bars arranged outside the channels and parallel to said U-irons.

In heat exchangers of this kind the heat exchange takes place in an indirect manner and any direct contact between the different media should be avoided. The demand for absolute tightness between the channels charged with different media has not been fully metby prior known heat exchangers. It has proved especially difficult to eliminate leakage at the edgeline between the bolt channel openings located perpendicularly with respect to each other. There is, however, a risk for leakage also at the holes in the plates which have been used in prior conventional heat exchangers. Leakage can further occur at the connections between different sections of the heat exchanger or at the connections of such exchanger and ducts for the two different media. It is a main object of the present invention to eliminate these drawbacks and to reduce the manufacturing costs and to facilitate the cleansing of the heat exchanger.

The present invention is mainly characterized in that the channel plates are joined at their edges in pairs by means of strips of sheet iron having a dimension corresponding to the Width of the channels, which strips in a manner known per se are folded to said channel plates, being stiffened and fixed at distinct mutual distances by means of U-shaped sheet irons and further characterized in that plane strips are arranged along a line, where the openings of the mutually perpendicularly arranged channels meet, one edge of said strips being fixed alongsaid line by means of welding or the like and the other edge of which is pressed to close alignment with the inner flanges of said U-iron frames by means of bolts.

A suitable performance of a heat exchanger in accordance with the invention for heat exchange between moist, hot air, for instance ventilation air exhausted from a locality, a drying plant or the like on one side and dry, cold air, for instance out-door air on the other side, is characterized in that the two outer channels of the heat exchanger are used for the dry, cold air and that they are outwardly enclosed by a plate fastened to one of said L-iron frames, said plate suitably having a greater thickness than the other channel plates and in that the edge strip of said channels is double bent along one of its edges and folded to the channel plate situated at the inner side of the channel, whereas said edge strip at its other edge is plane and extending out over the outer exchanger with ducts or the like.

2,828,947 Patented Apr. 1, 1958 plate and fixed between one of said L -iron frames and one of the U-iron frames of the framework.

Other features of the invention will be evident from the accompanying specification and drawings as well as the claims. V

' The invention will now be described more in detail with reference to the accompanying drawings in which:

Fig. l is a perspective view of a heat exchanger and its ducts according to the invention and Fig. 2 illustrates a detail of the heat exchanger along the section line. II-II of Fig. 1 land lastly Fig. 3 illustrates a detail of the heat exchanger along the section line IIIIII of Fig. 1.

In Fig. l a heat exchanger is designated 1, said heat exchanger in the shown embodiment consisting of two mutual similar units designated 2. The heat exchanger is erected on a base 3 provided with an inlet 7 and an outlet 8 for the wet air. 4 designates a hood for the conduction of the wet air from one unit to the other of the heat exchanger. The entrance of the out-door air is designated 5, said air being discharged at 6. 9 represents a duct for the out-door air and 10 is a corresponding duct for the wet air in case the heat exchanger is used for such media. The partition walls between the different channels of the heat exchanger consist of plane plates 11. According to the invention there are U-shaped stiffening sheet irons arranged in the channels between the plates. The channel plates are folded to end strips 14 of sheet iron. The channels of each unit are bonded together by means of a frame-work, consisting of frames of L-irons 15 and U-irons 16 and by means of transversal bars arranged outside the channels and parallel to said U-irons.

In the drawing of Fig. 2, 16 designates one of the frames of U-irons. 16a designates the web and 16b and the flanges of the U-irons in said frame. 16d and 16e stand for holes for bolting together the heat 17 stands for plane strips of sheet iron, said strips at one of their edges 1761 being welded to one edge of the channel openings along a line, where the openings of the mutually perpendicularly arranged channels meet. The strip is pressed by means of the bolt and nut 18 to close alignment With the inner flanges 16c of said U-iron frame. 19 designates a packing and 20 is a flat iron along the flange of the frame for the purpose of securing a proper alignment.

In Fig. 3 the elements shown in Figs. 1 and 2 have the same designations. 21 designates end strips for the outer channel 9. 21a designates the fold between the strip andthe adjacent channel plate 11 and 21b stands for the outer plane edge of the strips, said edge being pressed between the above mentioned elements 15, 16 by means of the bolt and the nut 23. 24 designates a. packing and 22 is a rivet joint between the L-iron frame 15 and the outer channel plate 12.

What I claim is: v

1. In a heat exchanger comprising a plurality of alternately arranged horizontal and vertical air ducts disposed in side by side relation, a plurality of vertically extending spaced parallel partition walls, means joining adjacent pairs of said partition walls together along opposite side edges thereof to define said vertically extending air ducts, strip members mounted in engagement with the opposite end edges of alternate pairs of said partition walls to define said horizontally extending air ducts,-said strip members being folded downwardly and inwardly into interlocking engagement with said alternate pairs of said partition walls, flat plate members mounted adjacent the ends of said strip members and extending outwardly therefrom, means securing said plate members to said strip members, a supporting frame surrounding said 3 partition walls, fastening means securing said plate members to said supporting frame, and gasket material disposed intermediate said plate members and said supporting frame operable topreyent leakage between said horizontally and vertically extending air ducts.

2. Apparatus in accordance with claim 1 wherein the outer walls at opposite sides of said heat exchanger are thicker than the partition walls, and members at opposite sides of said heat exchanger and connected to outer partition walls extend outwardly therefrom into engagement with said supporting frame.

3. Apparatus in accordance with claim 1 wherein the partition walls of each of said alternate pairs of said partition walls are disposed closer together than the partition walls of each of said adjacent pairs of partition walls, and the width of said strip members is at least as small as the distance between the walls of said alternate pairs of said partition walls.

4. Apparatus in accordance with claim 1 wherein stiflening members are disposed between the partition walls of each of said alternate pairs of said partition walls in engagement with said partition walls, said stiffening members extending longitudinally of said horizontally extending air ducts and positioned in spaced parallel relation to said strip members.

References Cited in the file of this patent UNITED STATES PATENTS 765,857 Rasner July 26, 1904 1,409,967 Prat Mar. 21, 1922 1,597,678 Fisher Aug. 31, 1926 1,750,850 Mantle et al. Mar. 18, 1930 1,761,173 Bluemel June 3, 1930 2,064,928 Lewis Dec. 22, 1936 2,143,269 Hubbard Jan. 10, 1939 2,728,561 Hager Dec. 27, 1955 

